Air-vent-controlling mechanism for centrifugal pumps



April 28, 1931. 1,803,191

7 AIR VENT CONTROLLING MECHANISM FOR CENTRIFUGAL PUMPS 1. c. JENNINGS Filed Aug. 2, 1926 INVENTQR JET-6:259 (1' J") By liilhl fhii 1 1o ter inlet of such atented pr. 28, 19 31 .mVING C. JENNINGS, OF SOUTH NORWALK, CONNECTICUT AEr-VENT-CONTROLLING MECHANISM FOR CENTRIFUGAL PUMPS Application filed August 2, 1926. Serial No. 126,487.;

This invention relates to mechanism for controlling an air vent pump under certain conditions of operation and particularly relates to such pumps when normally operated under a positive head of water.

Such pumps are largely used for marine purposes and under'conditions such as are commonly encountered on ship-board, the waa pump is frequently lifted above the normal water line by the roll of the intake pipe of the pump during the brief interval in which the intake pipe is uncovered. If this rocedure is several times repeated, an

air poc et is formed in the pump casing an the pump becomes air bound and practically inoperative.

My invention is not limited to marine use, so however, as similar operating conditions may arise from other causes, such as a widely fluctuating water supply.

It is the object of my invention to provide venting mechanism for a centrifugal pump operative to promptly release such small portions of air as soon as they enter the water passages and easing of the pump. Preferably the venting mechanism is controlled in its operation by the head of water .on the pump intake.

'An important feature of my invention relates to the provision of means for opening the vent as the water level falls and for closing the vent as the water level returns to normal position.

My invention further relates to arrange- -ments and combinations of parts which will be hereinafter described and more particu larly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings in which Fig. 1 is a cross section of a ship with my improved pumping apparatus installed there- 1n; Fig. 2 is anenlarged side elevation, partly in section, of thejpumping apparatus shown in Fig. 1; and I Fig. 3 is a sectional elevation of the apparatus shown invFig. 2.

Referring to the drawings, I have indicated for .a centrifugal p Air instead of water then enters the;

enters shallow water, however,

d thus taking the water supply a centrifugal pump 10, preferably of the imeller type, installed in the hull of a ship S and having an inlet pipe 12' and a delivery pipe 13. An intake pipe 14 is connected to the inlet pipe 12 and is provided with it shutoff valve 15. A second intake pipe 16 is also connected to the ipe 12 and is provided with a shut-ofi' valve 1%.

In'the usual operation of the apparatus, the valve 15 is open and the valve 17 closed when the ship is in deep water, thus drawing the water supply through the pipe 1 1 which is always submerged. When the ship it is desirable to close the valve-15 and open the valve 17, through the pipe 16 from a point somewhat removed from the bottom of the harbor, this change in operation sible the drawing of sand and gritty water into the pump 10.

When the intake pipe 16 is in use, however, the intake is much nearer the surface of the water and if the sea is rough, the ship frequently rolls suificiently to raise the pipe 16 intermittently above the water level, thus allowing more or less air to enter the pump 10. If any considerable amount of air thus enters the pump, the pump becomes air bound and practically inoperative until the air is in some way removed from the pump casing.

In carrying out my invention, I have provided means for automatically venting the centrifugal pump and preventing the accumulation of air therein. For this purpose I preferably provide a closed air chamber 20 above the casing of the pump 10, to which the cham-. ber 20 is connected by a pipe 21. The cham ber 20 is provided with an outlet pipe or vent 22, the inner end of which may be closed by a valve 23, operated by a float 24 in the air chamber 20. A check valve 25 is provided in the vent pipe 22 and a by-pass 26 connects the casing of the pump 10 to the upper part of the air chamber 20.

The pump 10 is shown herein as being of the single inlet type, with the casing so constructed that any air entering through the stufling box 30 may pass upward through the passage 31 and pipe 21 to the air chamber2Q.

being made to prevent as far as posleakage, as well as air entering through the intake pipe. It will be understood, however,

that the invention is equally applicable to centrifugal pumps of the double inlet type.

Having described the construction of a preferred form of my improved pumping apparatus, the method of operation thereof is as follows: Under normal conditions, the pump 10 operates under a positive head, with the water level above the float 24. The float is thus raised, closing the vent pipe 22, and the pump operates in the usual manner to draw water through the intake pipe 14 or 16 and to discharge the same through the pipe 13 for engine cooling, fire, sanitary or other purses. i

If the intake becomes temporarily uncovered and air enters through the pipe 12 to the casing of the pump 10, the air immediately passes upward through the pipe 21 to the chamber 20, while at the same time the float 23 drops, due to the fall of the water level. The air then passes out of the vent pipe 22 and as soon as the intake pipe is again submerged, water can flow freely into the pump casing and the pump Will again become operative. As soon as the water rises to the level of the float 24,the valve 23 is closed and no water-is permitted to escape through the vent Ihe check valve 25 is provided to prevent air from being drawn into the chamber 20 and pump 10 through the vent pipe 22, if the pump 10-operates at any time under a negative head. When this occurs, the check valve will promptly close, shutting oif the pipe 22. a

The by-pass 26 is provided to prevent the trapping of water in the air chamber 20, as otherwise when air enters the pump the water in the air chamber 20 might encounter considerable difficulty in flowing downward throughthe pipe 21 against the pressure of the air attempting to rise through the same pipe. With the construction shown, however, the air can flow upward through the by-pass 26, thus breaking the vacuum in the chamber 20 and allowing the water contained therein to flow down through the pipe 21 into the casing of the pump 10.

I have thus provided pumping apparatus for use wherever a centrifugal pump operates under a positive head and effective to remove air from the pump whenever necessary, without the use of an air pump or other complicated apparatus for this purpose.

Having thus described my invention and the advantages thereof, I do not wish tobe limited to the details herein disclosed otherwise than as set forth in the claims, but what head, and a venting device therefor comprising an air collecting chamber positioned above said centrifugal pump, said chamber communicating with the inlet water'passage of the pump and having an air outlet from said chamber, and means toclose said outlet when the head on the inlet side of said pump rises to a predetermined level.

2. Pumping apparatus having, in combination, a centrifugal pump having a casing and normally operating under a positive head, and a venting device therefor comprising an air collecting chamber positioned above said centrifugal pump, said chamber communicating with the inlet water passage of the pump and having anair outlet from said chamber, and means to close said outlet when the head on the inlet side of said pump rises to a predetermined level, said appara tus having also a by-pass air connection from said pump to the upper part of said air cham- .and normally operating under a positive head, and a venting device therefor comprising an air collecting chamber positioned above said centrifugal pump, said chamber communicating with the inlet waterpassage of the pump and having an air outlet from said chamber, and means to close said outlet when the head on the inlet side of said pump rises to a predetermined level, said apparatus having means also to prevent reverse flow of air through said outlet to said air chamber 1whedn said pump operates under a negative lea In testimony whereof I have hereunto affixed my signature IRVING C. JENNINGS. 

